Ch. 28 Sec. 2 The Moon

Reaching for the Moon  Soviet Union launched Sputnik I in 1957 –First step into understanding our space  1961, Soviet astronaut Yuri A. Gagarin became first human in space  U.S. Project Mercury launched first American, Alan B. Shepard, in space: 1961  1969, Apollo Program landed Armstrong and Aldrin on the moon: Apollo 11

Lunar Properties  Our moon, one of the largest known moons  Only moon for the inner planets  Only moon that is solid and rocky, others are ice  Moon is 27 % of Earth’s radius

Lunar Surface  Lunar surface is quite dark –The albedo is only.07% reflective –Albedo is the amount of sunlight reflected –B/c of no atmosphere:  127 o C in sunlight  -173 o C in darkness

Lunar Surface  No erosion except that of other impacts  Highlands –Light in color –Mountainous: heavily covered with craters –Impact craters: Ejecta and Rays

Lunar Surface  Mare or Maria –Dark smooth plains –Rilles: valley like structures

History of Moon  Moon is aged from bil. Yrs. Old  Moon heavily bombarded in first 800 mil yrs –Resulted in breaking & heating of rocks –Formed loose ground layer known as regolith

Moon tectonics  Infer from seismometer data that moon has layers  B/c of known volcano activity & magnetic field, little to no tectonic act. On moon

Moon formation Theories  Capture Theory –Beginning of solar system, an object ventured to close to earth –Got caught in the gravity field –Problem: earth and moon of similar elements  If came from somewhere else, would be different elements

Moon formation Theories  Simultaneous Formation Theory –Earth and moon formed in general area and the same time –Moon did not have to be slowed down –Problem  Different accounts of Iron on moon than Earth

Moon formation Theories  Impact Theory –Gigantic collision on earth that ejected into air –Materials merged together to form the moon –Iron deficient crust and all water would have evaporated on collision

Impact Theory